Dental amalgam polishing composition comprising stannous silicate {11 {11 {11 {11 {11 {11

ABSTRACT

Polishing compositions comprising stannous silicate, SnSiO3, having particles laying in the range of up to about 90 microns as an essential active ingredient are useful in polishing amalgam restorations, especially silver amalgam restorations.

1 i K M Inventor Joseph C. Muhler Indianapolis, Ind. Appl. No. 2,359 Filed Jan. 12, 1970 Patented Oct. 26, 1971 Assignee Indiana University Foundation Bloomington, Ind.

DENTAL AMALGAM POLISHING COMPOSITION COMPRISING STANNOUS SILICATIE SnSiO 6 Claims, No Drawings Int. Cl 1B24d 3/02,

Field of Search 424/48-58;

[56] References Cited UNITED STATES PATENTS 1,483,224 2/1924 Hamel i 51/307 2,389,352 11/1945 Fisher 51/308 2,694,004 11/1954 Coffeen 51/308 3,042,509 7/1962 Soderberg 51/305 3,071,455 1/1963 Harman et a1. 51/308 3,141,273 7/1964 Sarofeen r. 51/305 3,257,282 6/1966 Muhler 51/298 Primary Examiner-Donald J. Arnold Attorneys-Ronald L. Engel, Daniel W. Vittum, Jr., Gomer W. Walters and John A. Waters ABSTRACT: Polishing compositions comprising stannous silicate, SnSiO;;, having particles laying in the range of up to about 90 microns as an essential active ingredient are useful in polishing amalgam restorations, especially silver amalgam restorations.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the polishing arts, and more particularly to a polishing composition especially designed for use in connection with dental amalgam materials.

2. Description of the Prior Art Dental practitioners have, of course, long know of the desirability of all restorations in the oral cavity having an extremely high degree of luster or smoothness in order to have not only a more desirably aesthetic appearance, but also in order to decrease the rate of accumulation of various types of deposits on the restoration in the oral cavity (e.g., pellicle, plaque, oral debris, stains, surface oxides and sulfides, and the like), and to prevent the development of mouth odors. At present, different procedures must be employed for different types of restorations. For example, in the case of amalgam restorations, especially silver amalgams, the accepted procedure typically involves a first step of polishing with flour of pumice in order to smooth" the gross irregularities in the amalgam surface remaining from the hard carving of the amalgam, thereafter a second polishing step, utilizing conventionally available and used polishing materials such as tin oxide, SnO is carried out.

In spite of the use of the two-step process, the degree of polish obtained is not as high as is desired and, in addition, the necessity for accomplishing a'two-step process occupies valuable professional time which could be devoted to other therapeutic or hygienic dental work. Furthermore, the gross polish employed in the prior art processes results in the loss of desirably carved surface integrity of the restoration and serves to destroy the amalgam overhang of the margin of the cavity preparation.

As a result, a prime object of this invention is to provide a polishing composition capable of imparting a high degree of polish to dental amalgam in a one-step polishing process.

A related object is to provide a composition of the character described which may be used in a one-step process in treating amalgam restorations so as to render them less susceptible to the reaccumulation of oral debris.

A further object is to provide a composition of the character described which permits the development of high surface luster on the restoration without losing the integrity of the carved surface and without the loss of amalgam from the cavity margin.

SUMMARY OF THE INVENTION The foregoing and other objects, advantages, and features of the present invention may be achieved with a polishing composition adapted for application to dental amalgam restorations and comprising as its essential active ingredient stannous silicate, SnSiO having particles lying in the range of up to about 90 microns particle size. Preferably, the stannous silicate particles are distributed such that the majority thereof are less than about 15 microns particle size, preferably less than about 5 microns particle size. DETAILED DESCRIP- TION OF THE PREFERRED EMBODIMENTS In its broadest aspects, this invention relates to the use in a cleaning and polishing composition adapted for use in polishing dental amalgam restorative materials of stannous silicate, SnSiO as the essential cleaning and polishing component. More specifically, where tin silicate having particles lying in the range of up to about 90 microns particle size is employed, silver amalgam restorations may be finished to a high degree ofluster in a one-step polishing process.

The size of particles in polishing compositions can be expressed in a number of ways, one of the most common of which is means diameter," i.e., the average diameter ofa particle (as determined by appropriate measurement such as by a flotation process, by electron diffraction comparison with known styrene balls, or by light microscopy techniques), with 2 the number of such particles in each given diameter range being expressed on weight percentage basis. As hereinafter utilized, the term particle size "refers to such a mean diame ter value.

As noted, the particles of SnSiO; employed in accordance with this invention fall generally within the range of up to about microns particle size. Preferably, the particles are distributed such that the majority thereof are less than about 15 microns particle size, preferably less than about 5 microns particle size.

The following Examples give particle size distributions for preferred stannous silicate agents in accordance with this invention.

EXAMPLE 1 Particle Size Range Weight Percent EXAMPLE ll Particle Size Range Weight Percent The preparation of suitably sized particles of the constituents of the compositions of the present invention may be accomplished by conventional techniques well known to the art. Basically these these techniques involve milling stannous silicate, followed by standard screen sifting (or air separation) to segregate the desired particle sizes. Various milling techniques (e.g., hammer and ball milling) may be utilized in order to obtain the desired surface configurations.

As is well known in the art, hammer mills utilize a high speed rotary shaft having a plurality of hammers or beaters mounted thereon. The hammers may be T-shaped elements, bars, or rings fixed or pivoted to the shaft or to discs pivoted to the shaft. The shaft runs in a housing containing grinding plates or liners. The grinding action results from the impact between the material being milled and the moving hammers. When the ore is milled by attrition techniques such as hammer milling, relatively rough, jagged particles are produced. Particles having such jagged surface configurations generally function, from a surface cleaning standpoint, in a relatively superior manner as compared to more smoothly configured particles.

Similarly, a ball mill comprises a cylindrical or conical shell rotating on a horizontal axis which is charged with a grinding medium such as balls of steel, flint, or porcelain. The grinding is accomplished by the tumbling action of the balls on the material to be ground. Particles of ore treated in a ball mill of the character described have relatively smooth surface configurations and function relatively better from a polishing standpoint than more jaggedly configured particles.

In addition to the described milling and sieving techniques, the stannous silicate ores in question may be physically or chemically treated (e.g., by acid washing), in order to remove undesirably impurities prior to compounding. Preferably, the SnSiO, agents of this invention are formed by a ball milling procedure.

As noted above, the stannous silicate forms the essential cleaning and polishing component of the compositions of the present invention. Preferably, the stannous silicate itself is formulated in stick or powder form for direct manual application to the restoration, although the component may be diluted with water in the ration of about 2.6 grams of SnSiO to 2.0 mls. of water.

Compositions of exemplary polishing stick formulations in accordance with this invention are given in the following Examples.

EXAMPLE I Ingredient Z: By Weight Polyethylene Glycol (Carbcwax 01500) 25 Polyethylene Glycol (Carbowax M540) 25 SnSiO, (Example ll) 50 EXAMPLE II Ingredient By Weight Beeswax 40 SnSiO; (Example ll) 60 In use, after the practitioner has put the dental amalgam restoration in place, allowed it to harden, and has carved it to the desired surface configuration, he may polish it in one step using the agent of the present invention, advantageously through the use of a dental engine, handpiece, prophy angle, and rubber cup. Ordinarily, the agent or composition is applied in the presence of a lubricant, usually water, in order to minimize the development of undesirably heat. Where applied in paste form, the agent may vary its own lubricant in a preformulated form.

EXPERIMENTAL EVALUATIONS In order to establish the effectiveness of the polishing agents of the present invention, polishing values were evaluated utilizing the following procedure. Conventional dental amalgam alloys were placed in specially prepared polyester blocks using accepted and standardized dental procedures for trituration and placement of the alloys. The amalgams were then polished in the conventional manner, utilizing a dental engine, handpiece, prophylaxis angle, and a rubber cup, with the specific polishing agent. The amount of luster imparted to the alloys was quantitively determined using a reflectometer technique (J. Periodontology, 37: 200, 1966), with a greater amount of reflected light and hence a greater galvanometer reaching .being indicative of a smoother surface and greater relative polishing efiectiveness.

After the maximum reflectance of the dulled tooth is determined, the tooth is polished with a dental engine, handpiece, prophylaxis angle, and rubber cup with the indicated specific polishing agent.

Data obtained for two standard commercially available alloys with the compositions of this invention and with other polishing agents for comparative purposes are reported in Table I.

TABLE l Amalgam Polishing Agent Amalgam Polishing Score Two-step process.

The polishing scores reported in Table l establish the very substantial superiority of the agents of the present invention as dental amalgam polishing agents.

In accordance with the present invention there has therefore been found a wholly satisfactory tin silicate polishing composition which may be employed to polish dental amalgam restorations, especially silver amalgam restorations, quickly and conveniently through the use of a one-step process, and without the necessity of time consuming multiple treatments and yet with superior results.

I claim:

1. A composition adapted for use on dental amalgam restorative materials comprising:

an inert carrier; and

about 20-90 percent by weight of stannous silicate, SnSiO having particles lying in the range of up to about microns particle size.

2. A composition, as claimed in claim 1, wherein the majority of the particles lie in the range of up to about l5 microns particle size.

3. A composition, as claimed in claim 2, wherein the majority of the particles lie in the range of up to about 5 microns particle size.

4. A method of polishing dental amalgam restorative materials comprising the unitary step of applying thereto in the presence of an invert lubricant, stannous silicate, SnSiO having particles lying in the range of up to about 90 microns particle size, and polishing said amalgam therewith.

5. A method, as claimed in claim 4, wherein the majority of the particles lie in the range of up to about 15 microns particle size.

6. A method, as claimed in claim 5, wherein the majority of the particles lie in the range of up to about 5 microns particle size. 

2. A composition, as claimed in claim 1, wherein the majority of the particles lie in the range of up to about 15 microns particle size.
 3. A composition, as claimed in claim 2, wherein the majority of the particles lie in the range of up to about 5 microns particle size.
 4. A method of polishing dental amalgam restorative materials comprising the unitary step of applying thereto in the presence of an invert lubricant, stannous silicate, SnSiO3, having particles lying in the range of up to about 90 microns particle size, and polishing said amalgam therewith.
 5. A method, as claimed in claim 4, wherein the majority of the particles lie in the range of up to about 15 microns particle size.
 6. A method, as claimed in claim 5, wherein the majority of the particles lie in the range of up to about 5 microns particle size. 